Harvard study reveals nuanced role of ultra-processed foods in a healthy diet

A comprehensive Harvard-led study challenges the perception of processed foods as inherently unhealthy, emphasising the importance of overall nutritional quality and moderation for sustained health benefits.

A diet can include some ultra-processed foods and still be healthy, according to a Harvard-led study that suggests overall nutritional quality matters more than the degree of processing alone. The research, which followed more than 200,000 adults for around 30 years and was published in The Lancet Regional Health-Americas, found that people who ate the most ultra-processed foods had a higher risk of cardiovascular disease overall. But the picture was more nuanced: foods often treated as dietary villains, including some breakfast cereals, bean products and fortified plant milks, can fit into a balanced pattern of eating, while some foods that sound wholesome may still need to be limited.

That distinction is important for families trying to make practical choices at the supermarket. Dietitian Sarah Keogh, founder of Eatwell Nutrition, says the nutrients in a food matter more than the label attached to it. A food low in saturated fat, sugar and salt and high in fibre is likely to support health, she says, while the opposite combination carries risk whether the item is classed as processed or not. Dr Xiaowen Wang, one of the Harvard study authors, made a similar point, saying a healthy plant-based diet rich in whole grains, fruit, vegetables, nuts, legumes and healthy plant oils can still be beneficial even if it includes some processed foods.

Among the better options are baked beans, which provide fibre and plant protein, and fortified soy milk, which offers protein with less saturated fat than cows’ milk. Plain wholegrain cereals such as Weetabix and bran flakes can also help raise fibre intake, which most people fall short of, while jarred tomato sauces and some salad dressings may be reasonable shortcuts when they are low in added sugar and unnecessary additives. Fish fingers made from fish rather than fillers can also have a place on the plate, especially when they deliver omega-3 fats, iodine, selenium and protein. Even ketchup can contribute some lycopene, the antioxidant linked to cooked tomatoes, though portion size still matters.

At the other end of the scale, the Harvard work supports caution around foods that may look natural but carry more downside than many realise. Red meat remains limited in public health guidance because of its saturated fat content and its link with bowel cancer risk. Coconut oil is another example: despite its natural image, it is highly saturated and can raise LDL cholesterol. Maple syrup and fruit juices are no free pass either, with both contributing significant sugar. For parents and caregivers, the practical message is straightforward: focus first on the nutrient profile, not the marketing, and use processing level as just one clue among many.